1. Field of the Invention
The present invention relates to apparatus for performing horizontal mixing, liquid mixing and vortex mixing. More particularly, the present invention relates to a single mixer for performing the above-described separate mixing operations and other processing operations.
2. Description of the Prior Art
Horizontal mixers for mixing of solids, semisolids, and pastes are well known. Examples of horizontal mixers are disclosed in U.S. Pat. Nos. 2,750,163, 3,027,102 and 3,162,428. Horizontal mixers typically contain a plurality of plow-shaped mixing elements which are mounted radially from a central drive shaft. Upon rotation of the central drive shaft, the plow-shaped elements sweep out an annular volume in proximity to the inner wall of a drum to cause the material to be thrown up and away from the inner wall of the drum toward the central drive shaft to produce substantial mixing action. Horizontal mixers may additionally include a deagglomerating impeller which projects orthogonally inward from the inner surface of the mixing drum toward the central drive shaft for use in controlling particle size and the dispersing of viscous liquids within the drum.
Mixers are also known which have a vertically projecting central drive shaft upon which a vertical impeller is mounted at the bottom of the mixing chamber. The drive mechanism for the drive shaft of the vertical impeller may be projected upward from below the bottom of the mixing chamber or projected downward from above the mixing chamber. Typically for mixing liquids, the drive shaft is projected downward from a drive mechanism located above the top of the mixing chamber and is rotated at high speeds such as 3000 rpm. Typically for producing vortex mixing suited for granulation, the drive shaft is projected upward from a drive mechanism located below the mixing chamber and is rotated in the range of 500 to 600 rpm.
Each of the above-described prior art mixing systems are available as special purpose mixers designed for performing a single type of mixing action. Because of the design of these mixers to perform a single mixing operation, they are not suited for the performing of diverse types of mixing operations for the mixing of solids and liquids which require a drive shaft for driving mixing elements to be positioned in either horizontal or vertical orientations. Therefore to perform the above-described diverse mixing operations it is necessary to have special purpose mixers dedicated to performing only one type of mixing operation with the concomitant high expense associated with the purchase of separate pieces of equipment.
Mixing equipment is commercially available for performing granulation which has a mixing chamber that is rotatable through an angle of approximately 60.degree.. This mixer has a mixing arm which is rotated in two directions under the control of a variable speed adjustment. This mixer is designed for the single purpose of granulation. The mixer is not positionable in horizontal and vertical orientations for performing diverse mixing oprations requiring mixing elements to be positioned in these angular orientations.